Stability Improvement of Perovskite Solar Cells by Compositional and Interfacial Engineering

Solar cells based on metal halide perovskites continue to approach their theoretical efficiency limits thanks to worldwide research efforts. The next challenge is to develop perovskite devices that can retain these efficiencies but exhibit acceptable degradation and decent stability for real-life practical applications. The degradation can be triggered and significantly affected by external environmental factors, such as moisture, oxygen, light, and heat. Although the encapsulation allows effective suppression of moisture- and oxygen-induced degradation, the reduction of light degradation and heat degradation is primarily dependent on the improvement of materials and interfaces of cells. Herein, the degradation mechanisms caused by light and heat are elucidated for each of the major layers in the device. The methodologies for the corresponding degradation reduction and stability enhancement are interpreted from compositional and interfacial engineering strategies with quantitative analysis including the site-based substitution in perovskite lattice, doping in charge transporting layers, passivation by using various materials (small molecules, polymers, ligands, perovskite quantum dots, and low-dimensional perovskites), and a protective layer for vulnerable layers. This Review will provide important insight into degradation suppression and stability enhancement of perovskite solar cells and give a clue to optimal design toward high-efficiency and stable devices.

Automated summary

Solar cells based on metal halide perovskites are approaching their theoretical efficiency limits with global research efforts, but facing challenges in degradation caused by external factors and the improvement of materials and interfaces for stability enhancement.